Pneumatic switching member



Feb. 14, 1967 M. MAMY 3,303,999

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Feb. 14, 1967 M. MAMY PNEUMATIC SWITCHING MEMBER 4 Sheets-Sheet 4 FiledSept. 16, 1963 0 0 O P PA P mm K P P P DH il ll liii 4 A n F I I I IIIII a 1-1 InUEnTOR max-c2) i United States Patent 3,303,999 PNEUMATICSWITCHING MEMBER Marcel Mamy, 11 bis, Rue Roquepine, Paris, France FiledSept. 16, 1963, Ser. No. 309,079 Claims priority, application France,Sept. 18, 1962, 909,775 Claims. (Cl. 235-201) The advantage of the useof compressible or incompressible fluids, such as air or oil, for thetransmission of information requires no further proof and many processesand industrial installations now utilise hydraulic or pneumatic membersfor continuous control and regulation.

The position occupied by these pneumatic or hydraulic systems, despitethe development of corresponding electronic systems, is justified for anumber of reasons:

The processes to be controlled often possess the characteristics oflow-pass filters, the response times of the controllers being negligibleas compared with the correction times of the controlled installations.

The control members are simple, robust and sufficiently accurate, whileproviding high power gains for reasonable energy consumption, cost andmaintenance.

Pneumatic or hydraulic elements are not attended by certaindisadvantages inherent in electric systems, such as, for example, arcingor the necessity to keep the operating temperatures at a relatively lowlevel.

The object of this invention is to contribute to the development ofindustrial sequentially acting logical and automatic control systems.

An elemental diaphragm-type pneumatic switching member is known whichcomprises four successive chamhers separated by three paralleldiaphragms. These diaphragms are mechanically connected together by ashaft, the assembly forming a unit movable in the direction of theshaft. Each chamber is connected to a pressurisedfluid pipe, the saidfluid generally being compressed air which supplies a particular controlsignal. The movable unit is disposed between two nozzles through whichan operating signal passes and which are alternately closed by themovable unit, depending upon the position of the latter. The surfaces ofthe diaphragms separating the chambers may be varied by the positioningof diaphragms which reduce the active surface of the movable diaphragm.In this four-chamber member, the two central chambers are, for example,separated from one another by a central diaphragm of large surface,these central chambers being separated from the respective end chambersby diaphragms of smaller surface than the central diaphragm. Eachchamber, therefore, comprises either one diaphragm or two diaphragms,the latter two having different surfaces. A pressure introduced into oneof these two-diaphragm chambers will, therefore, generate a force whichwill be proportional to the surface difference of the two diaphragms anddirected towards the larger of the two surfaces. The resultant of theforces applied to all the diaphragms will, therefore, determine thedirection of movement of the movable unit, so that the nozzle will "beclosed.

These four-chamber pneumatic members, in combination with otherparticular pneumatic members, make it possible to provide the majorityof the logical elements generally employed in pneumatic computers andindustrial sequentially operating automatic control systems.

However, these fourcham-ber members have the disadvantage that theynecessitate the use of other members based upon different structures, sothat complete standardisation of the elements is not possible. Moreover,some logical circuits necessitate too many four-chamber elements, whichincreases the overall size of the appara tus.

The object of this invention is to contribute to the provision oflogical systems and industrial sequentially operating automatic systemsbased upon a minimum number of standard pneumatic elements.

The present invention concerns an elemental pneumatic cell of the typecomprising diaphragms bounding internal chambers connected to externalducts, a movable unit and nozzles connected to external ducts, the saidnozzles being adapted to be closed by the movable unit.

The elemental pneumatic cell according to the invention has theadvantage that it can be employed alone to perform the functions of arelay, a switch, a discriminator or a comparator for logical signals andall basic functions of logical discrete-signal structures.

When employed in combination with a very limited number of particularpneumatic elements such as pneumatic resistances and capacitances, thiscell solves all the problems of automatic control which necessitate bothelements performing elemental logical operations and elements involvinga time factor. Thus, it is possible by combining these various circuitsto build up "universal elements such as the McCullough and Fitts neuron.

The elemental pneumatic cell according to the invention is distinguishednotably in that it comprises at least six chambers separated bydiaphragms having alternately large and small active areas or surfaces,one of the said chambers being constantly connected to a return pressuresource of constant value lower than the value of the fluid supplypressure of the pneumatic element.

Another object of the invention resides in the connection of theelemental cell as a comparison member which compares the variablepressures with a predetermined value of the return pressure.

A third object of the invention is the connection of the cell as amemory or storage cell for registering a signal and restituting it bythe action of a return-to-zero signal.

Further objects and features of the invention will become apparent inthe course of the following description.

The following description of the invention will comprise a detaileddescription of the structure of the cell according to the invention, astudy of the possibilities offered by this cell in the performance of anumber of basic elemental operations and a study of a number of morecomplex pneumatic circuits which illustrate with particular clarity theadvantages afforded by the cell according to the invention.

It is to be understood that these embodiments .are here referred topurely by way of illustrative and non-limiting examples, because it isobvious that the possible combinations with cells according to theinvention and a number of other pneumatic members may be multiplied adinfinitum for the purpose of resolving any given problem, and that anyoperation, no matter how complex, will always be reduced, by analyticaldecomposition, to the combination of a limited number of elementaloperations.

Also, in order more clearly to illustrate the invention,

we shall set out a priori a number of particulars, which have nolimiting character.

FIGURE 1 illustrates diagrammatically a cell according to the invention.

FIGURE 2 is the symbolic representation of the cell according toFIGURE1.

FIGURE 3 is an example of the application of the FIGURE 6 is an exampleof the production of the logical product of two inverses. 7

FIGURE 7 is an example of the production of a delay.

FIGURE 8 is an example of the formation of the logical product of threevariables.

FIGURE 9 is an example of the formation of a memory or store.

FIGURE 1-0 is an example of the construction of mono stable circuit.

FIGURE 11 is an example of the construction of a multivibrator circuit.

FIGURE 12 is an example of the construction of a bistable circuit.

FIGURE 13 is an example of the construction of a dilemma circuit.

FIGURES 15a and 15b represent characteristic curves of a comparatorcomprising a four-chamber cell and of a comparator comprising asix-chamber cell according to the invention.

FIGURE 14 illustrates the system of characteristic curves which may beobtained with a comparator having a six-chamber cell according to theinvention.

FIGURE 1 is a diagrammatic representation of a cell according to theinvention. This cell comprises six chambers each connected to acompressed-air duct and numbered 3 to 8, the said chambers beingrespectively separated by five diaphragms. These diaphnagms, in thedescribed examples, have alternately and successively a surface oractive area of value s and a surface or active area of value S, S beinggreater than s. In FIGURE 1, the active or flexible area of thediaphragms is shown in heavy line as forming the center portion of eachdiaphragm.

Situated opposite the first diaphragm is the opening of the nozzle B fedby a compressed-air duct 2 at the pressure P Situated opposite the lastdiaphragm is the aperture of the nozzle B connected to a duct 1 throughwhich the output signal passes.

According to the invention, the cell comprises a return system whichacts on the movable unit and imparts thereto, in the inoperative state,a predetermined position. This return system consists of a force appliedto the movable unit by a constant pressure .of value kP introduced intoat least one of the six chambers of the cell. P being the value of thesupply pressure of the cell, k is a coeflicient lower than 1, chosen asa function of the ratio of the surfaces s and S. The pressuresintroduced into the chambers, or control pressures, will becalled P andwill be accompanied by indices as long as Ps represents the outputpressure. The atmospheric pressure will be taken as the referencepressure and will be symbolically represented in the figures by thesymbol reference potentia or earth of electric circuit diagrams. Thepositive direction chosen for orienting the various forces exerted onthe diaphragms is that of an arrow which extends from the nozzle Btowards the nozzle B For the sake of clarity of the text, a distinctionwill be drawn between the four chambers 5, 6, 7 and 8 which serve moreparticularly for the control of the movable unit. A positive force willbe exerted on the movable unit on application of pressure to thechambers 7 and 5, called the odd chambers, while a negative force willbe exerted on the movable unit on application of pressure to thechambers 8 and 6, called the even chambers.

' FIGURE 3 is an example of the use of the cell for the comparison ofanalogue signals. The chamber 3 is connected to the output duct 1. Thechamber 4 is connected to atmospheric pressure, an odd chamber, forexample the chamber 7, is connected to the constant pressure kP andthree control pressures P P and P maybe transmitted respectively to thelast three free chambers 6, and 8.

The resultant F of the pressure forces will be:

It will thus be seen that the direction of the force will 4 depend uponthe comparison between the value of the constant pressure kP fixed atWill, and of the sum of three pressures which vary in time.

P +P P kP the movable element will close the nozzle B and the outputpressure will be equal to P When the movable element will take up theinoperative position, the output pressure being zero (atmosphericpressure through the open nozzle B We have thus provided a comparator.By connecting in parallel a number of cells adjusted to variable returnpressures kP an analogue-todigital converter for the measurement P +P -Pis provided.

It was readily be appreciated that it is possible to Vary the expressionof the sum to be compared by manipulating the relative surfaces of thevarious diaphragms and the choice and number of the chambers into whichthe control pressures are introduced.

More especially, for digital signals, where the ratio Szs is made veryslightly higher than 1:1, the pressure P P being zero, the comparatorperforms the function of an amplifier, i.e., a very weak signal P givesrise to an output signal P of the maximum value P =P 1.

FIGURE 4 shows an example of the combination of the elemental cell withan amplifier of the nozzle-blade type in which the function of the bladeis performed by the chamber 3 of the elemental member. Depending uponthe position of the movable unit, the chamber 3 com- When ' municates ordoes not communicate with the atmosphere through the nozzle B and thesignal is either amplified or negligible.

An important use of this combination is the digital-toanalogueconversion of any quantities represented in the form of digits. If thesame chambers of a number of identical cells are connected in parallelat one end of a nozzle, these cells will perform a function identical tothat of monostable electronic flip-flops. The digital quantity is heresent in the form of a pressure to a number of cells which symbolicallyrepresent values graded as a function of a certain coding, for example abinary coding.

It is known that a nozzle-blade type amplifier delivers at its output apressure inversely proportional to the opening of the nozzle R, theopening of the nozzle being measured by the flow of the fluid passingthrough this nozzle. If the same chamber (for example, chamber 3) ofeach of a series of cells such as that of FIGURE 17, is connected Withthe nozzle of a single amplifier, the output pressure P of the amplifieris inversely proportional to the flow in the nozzle, this flow beingproportional to the number of the chambers 3 connected with theatmosphere, that is to the number of chambers not actuated when the biasis arranged so that each cell is normally in the open position. Adigital quantity P comprises a plurality of digits P P P P each digitrepresenting a given component of the quantity, and the output pressureP of the nozzle-blade type amplifier will be proportional to the numberof actuated cells and such an arrangement actually constitutes adigital-to-analogue converter.

The comparator according to FIGURE 2 operates both as an analogue signalcomparator and as a digital signal comparator. Moreover, with digitalssignals, it may have the function of a signal repeater (P =P =O) or ofa.

relay (P =0, K 0).

As a digital signal comparator, it affords additional advantages tocomparators which may be constructed with four-chamber cells Without anyreturn force. The presence of the two additional chambers makes itpossible to obtain a system of characteristics which are variable as afunction of the value of the pressure P;, and of the coefficient K (seeFIGURE 14).

On the other hand, four-chamber comparators have the defect ofexhibiting lack of determination for the output value 1 when the twopressures to be compared are equal (see FIGURE 15a, which shows thecharacteristic curve of P as a function of the difference P P in thecase of a four chamber comparator). 1

In the case of a six chamber comparator according to the invention, thecharacteristic curve has in fact a form known as a hysteresis curve 15bwith a stable position P for P =P (with P =0). If P is a constantpressure, the inoperative point may be either P =0 or P =P dependingupon the value of the difference P -kP as is apparent from FIGURE 14.

The hysteresis shape of the characteristic curve will be understood byreferring to FIGURE 15b, representing the characteristic curve of a cellconnected, for example, as illustrated in FIGURE 3. For sake of clarity,it is assumed that P =0. When P P =0, the biasing pressure KP keeps themovable element in its upper position and the output pressure P =0. WhenP -P reaches the value KP the movable element starts moving with acertain speed which depends on its inertia, and the movable elementreaches the lower position at a time when the value P P =n. It is to benoted that as soon as the nozzle 2 is open the pressure P in chamber 3helps in accelerating the movement of the movableelement. The inertia ofthe movable element is generally very small and owing to assistingpressure P A in chamber 3 the slope of the flank AN of the curve isalmost vertical, as it is shown in FIGURE 14. Referring again to FIGURE15 b, where the pressure P P starts to decrease, and reaches again thevalue KP the movable element does not move upward because of thepresence of the pressure P in chamber 3. The acting forces being (Pl-P2)K A S )+PA(s) the movable element will start moving when is alwayssmaller than KP A and the movable element will move when P -P =m (pointM of the curve) in the case of K s/Ss or P P =q (point Q of the curve)when K s/Ss. Thus depending on the case the characteristic curve of thecell will be either ANMM or ANQQ. It is pointed out that the hysteresiscurve exists even if the nozzle B is not fed with the pressure P owingto the slope of the flank AN but the width of the characteristic curvedepends essentially on the presence of the pressure P It will be seenhereinafter that the width of the curve may be still increased byconnecting a further chamber to the output of chamber 3, for example, asillustrated in FIGURE 9.

The six-chamber cell comparator has in addition the advantage that itdoes not require very accurate finishing in the positioning of thenozzles, such accuracy being fundamental to four-cell comparators owingto the instability of the latter when P =P FIGURE 5 and the followingfigures give a number of examples of the use of these cells as logicalcomputing elements. In these examples, all the control pressures cantake only one of two values 0 and P (digital signals).

The connection of the cell in accordance with FIGURE 5 makes it possibleto produce the logical sum of three variables P P and P The logical sumis obtained when the existence of at least any one of the threepressures produces the dispatch of an output signal P In order to dothis, two of these pressures are sent into the even chambers 6 and 8,the third being sent int-o the chamber 4, while one of the odd chambers5 is connected to the atmosphere, the other 7 receiving the returnpressure kP This is the pneumatic form of the OR cell known toelectronics engineers.

The connection of the cell in accordance with FIGURE 6 represents anexample of the performance of the socalled inversion operation. Thisoperation consists in obtaining a signal when the cell is in theinoperative state and in cutting off this signal as soon as one or morecontrol pressures are set up. It is symbolically written It will be seenthat in the absence of control pressure (neither P nor P the movableunit closes the nozzle B An output signal Ps therefore passes throughthe duct connecting the chambers 3 and 1. As soon as one of the controlpressures is introduced into an odd chamber, the movable unit changesover, thus connecting the output duct to the atmosphere. This is theform of the nor cell known to electronics engineers.

Such connections, in which the output signal is a function of thealgebraic sum of a number of pressures, may, therefore, be used aselemental discriminators for control loops.

The arrangement according to FIGURE 7 combines the elemental cell with adelay device. There is provided in the circuit for the admission of thecontrol pressure, of which it is desired to delay the action, anadjustable throttling R, and a reservoir C is connected in parallel.This device has the effect of inclining the generally very steep frontof the pressure wave constituting the control signal. This assembly RCincreases the time of the pressure rise proportionally to If 1 6 RC i.e.proportionally to RC in the substantially linear useful part of thecorresponding curve. The change-over of the movable unit, which takesplace only from a threshold fixed by the pressure kP will therefore bedelayed by the time necessary for the pressure of the control signal toreach this threshold. By varying R or C, the duration of the delay willbe modified.

FIGURE 8 provides an example of the formation of the logical product ofthree variables, that is to say, a signal is obtained when the threecontrol pressures, representing these three variables, existsimultaneously in the respective chambers. This device provides theequivalent of the AND cell known to electronics engineers. The pressuresP P and P arrive at the two even chambers 6 and 8 and at the nozzle B;respectively, the odd chambers 5 and 7 being connected to the returnpressure kP the chamber 4 being connected to the atmosphere. In thisembodiment in the static condition with P or P equal to O, nozzle B willbe closed due to the bias pressure ZkP which is greater than P or P butless than P +P Thus, the output P will be at atmospheric pressure.However, with both P and P applied, the cell will be actuated andchamber 3 will be connected to the output. If under these conditions Pis applied an output P equal to P will occur; if P is not applied, nooutput will occur. It should be noted that P need not equal P nor P solong as P +P is greater than ZkP FIGURE 9 illustrates a very importantelement in control or computing equipment. This is the memory or storewhich, in the other systems at present known, necessitates a minimum oftwo cells. In order to provide the storage device, the chambers 8 and 3and the nozzle B are connected to the output duct, the signal P to bestored is introduced into the chamber 6, and the return-to-zero signal(RAZ) arrives atthe chamber 5, the chamber 4 being connected to theatmosphere.

In the inoperative condition, the movable unit is subject to a force kP(S-s) and closes the nozzle B The output pressure P extracted at B istherefore equal to the atmospheric pressure. If an input signal P isapplied at 6, the equilibrium is broken and the movable unit moves awayfrom the nozzle B the chambers 8 and 3 then becoming filled andaccelerating the closure of the nozzle B The output pressure istherefore equal to the supply pressure and retains this value even if Preturns to zero.

7 As a matter of fact where the cell is open, that is when the movableelement is in the lower position the various forces acting upon themovable elements are:'

KPA(SIS)+PA(SS)+PA (S) When P returns to zero, a force equal to PA[S K(SS)] is still applied to the movable elementwhich will start moving onlywhen a return to zero signal (RAZ), greater than is applied to thechamber 5. The characteristic curve of such a memory cell is similar tothe curve illustrated in FIGURE b but with a still increased width.

FIGURES 10, ll, 12 and 13 give a number of constructional examples ofpneumatic circuits performing the same functions as the well knownelectronic circuits.

These constructions are distinguished by the fact that these circuitscomprise, apart from the pneumatic resistances and capacitances, onlyone type of elemental cell according to the invention. The applicationof these elemental cells makes it possible in addition to reduce thenumber of elements necessary for performing certain logical operations,owing to the fact that the so-called memory or store circuits requireonly one cell according to the invention and not at least twoconventional cells.

Another advantage is provided by the high degree of standardisationrendered possible by the cell according to the invention, because in allthese diagrams the chamber 8 and the nozzle B are connected, apart fromthe combination of the cell according to the invention, to an amplifierof the nozzle-blade type.

FIGURE 10 illustrates a monostable circuit obtained by combining theproperties of a cell connected as a memory or store and of a delaydevice.

The introduction of a signal P into an even chamber of the cell Aproduces, owing to the downward rocking of its movable unit, the passageof an output signal which is simultaneously to an even chamber of thecell B, through a delay system, and to an output Ps.

This delay system produces after a predetermined time, the applicationof a signal to an odd chamber of the cell A, which signal returns themovable unit to its inoperative position, which is the only stableposition. The circuit illustrated is simpler, but it is possible to usethe additional chambers of the feedback amplifying cell B to modify theproperties and the operating conditions of the monostable circuit byintroducing additional input signals such as P and P It is thuspossible, in accordance with the form of these signals,-either to retainthe monostable circuit in one position or the other, or to vary thereciprocal durations of the signal and of the dead time.

FIGURE 11 is a multivibrator circuit. It utilises four cells and a delaysystem. The frequency of the oscillations is a function of the responsetimes of the cells and of the delay, i.e. of the product RC previouslydefined. The operating cycle of the circuit is as follows: the supplyinlets being under pressure, the cell A supplies a signal which is sentto an even chamber of the cell C, of which the movable unit changes overand supplies in turn a signal which on the one hand is delivered at Psand on the other hand actuates a cell D provided with a delay device.The latter, after a predetermined time, sends a pulse which cuts off theoutput signal at the cell A and changes over the movable unit of thecell B, which in turn supplies a signal which, when introduced into anodd chamber of the cell C, closes the latter. The cell C in turn blocksthe output signal Ps'and connects with the atmosphere the signalsupplied by the chamber D producing the return to the initial state ofthe cells A and B, which are thus ready for a further cycle.

Here again, it is possible by means of auxiliary signals 8 either toretain the multivibrator in one of its positions (pressure P or P in theremaining odd chamber of the cell A or of the cell B), or to vary theperiod of the multivibrator or the form of the output signal (pressuresP and/ or P in the remaining chambers of the cell D).

FIGURE 12 illustrates a bistable circuit utilising four cells. Its cycleis as follows: an input signal is simultaneously sent to an even chamberof each of the cells A and B. This signal produces the despatch of apressure into an odd chamber, in the present instance the chamber 5, ofthe cell C, which then supplies an output signal Ps and simultaneouslydespatches a pressure to an odd chamber, in the present example thechamber 5, of the cell D, which in turn supplies a signal complementaryto Ps.

FIGURE 13 illustrates a dilemma circuit, i.e. a three-cell circuit whichrepresents the logical so-called dilemma function, which is written:Ps=(P -P )+(P -P that is to say, an output pressure is obtained whenonly one of the two control pressures P and P arrives, with theexclusion of a simultaneous arrival. Its operation is as follows: thecontrol pressure P is simultaneously sent to an even chamber of the cellA and to the supply nozzle B of the cell B. The control pressure P issimultaneously dispatched to an even chamber of each of the cells A andB.

The cell A is connected as an OR cell, of which the output feeds thesupply nozzle B2 of the cell C. The cell B is connected as an AND celland its output signal is transmitted to an odd chamber, in the presentcase the chamber 7 of the cell C. It will thu be seen that there canonly be an output signal from the cell C if the nozzle B2 is fed(existence of P or P and if the chamber 7 is connected to the atmosphere(no simultaneity of P and P Here again, secondary connections to theunused chambers make it possible to vary the operating conditions of theWhole arrangement (blocking, delay, etc.).

In conclusion, it will be seen that these cells can replace electronicdevices in all operations not requiring excessively high responsespeeds, which is the case in the majority of servomechanisms. All theexamples given have been chosen with six-chamber cells.

All the examples given above have been so chosen as to demonstrate thepossibilities of the cells according to the invention, i.e. ofsix-chamber cells having variablesurface diaphragms, comprising at leastone chamber into which there is introduced a constant pressure creatinga return force.

These cell afford the advantages hereinbefore described in pneumaticcircuits employed to resolve the usual functions of present-day modernarrangements.

For particular applications such as, for example, functions involving alarge number of variables, it is obvious that it is possible withoutdeparting from the scope of the invention to use cell having a largernumber of chambers, six being the minimum number of chambers by means ofwhich it is possible, together with the known logical elements, toperform certain functions such as the analogue or digital comparatorfunction or the memory or store function.

What is claimed is:

1. In a pneumatic logical circuit including bias means for supplying afluid with a constant selective biasing pressure and control means forsupplying fluids at signal pressures,

a logical cell, comprising:

a series of six chambers disposed contiguously, consecutive chambershaving common partition means including diaphragm means therebetween,said diaphragm means of first alternate ones of said partition meanshaving active areas of a first size and the diaphragm means of theremaining one of said partition means having active areas of a secondsize larger than said first size in a predetermined ratio,

a movable substantially rigid element mechanically 9 connecting togethersaid active areas of 'the diaphragm means and having a first end partand a second end part extending respectively into the first and the lastof said series of chambers,

said first chamber in said series including first nozzle means and saidfirst end part including closing means operable to close said firstnozzle means upon displacement of the movable element toward said firstnozzle means,

said last chamber in said series including second nozzle means formingan output and said second end part including closing means operable toclose said second nozzle means upon displacement of the movable elementtoward said second nozzle means,

the chambers having a smaller active area diaphragm means forming apartition thereof facing said first nozzle means being called evenchambers, the other chambers being called odd chambers, at least one oddchamber having an input connection supplied with said fluid at saidbiasing pressure,

at least one odd chamber having a signal input connection supplied withone of said fluids at signal pressures,

at least one chamber other than said first chamber being open to theatmosphere and said first chamber being connected with said output.

2. The combination defined in claim 1 wherein at least two even chambershave a signal input connection supplied With one of said fluids atsignal pressures.

3. In a pneumatic logical circuit including means for supplying a fluidwith a constant feeding pressure, means for supplying a fluid at aconstant biasing pressure lower than said feeding pressure and means forsupplying fluids at signal pressures,

a logical cell, comprising:

a series of six chambers disposed contiguously, consecutive chambershaving common partition means including diaphragm means therebetween,said diaphragm means of first alternate ones of said partition meanshaving active areas of a first size and the diaphragm means of theremaining one of said partition means having active areas of a secondsize larger than said first size in a predetermined ratio,

a movable substantially rigid element mechanically connecting togethersaid active areas of the diaphragm means and having a first end part anda second end part extending respectively into the first and the last ofsaid series of chambers,

said first chamber in said series including first nozzle means forminginput means supplied with said feeding pressure and said first end partincluding closing means within said first chamber operable to close saidfirst nozzle means upon displacement of the movable element in thedirection thereof,

said last chamber including second nozzle means forming an output andsaid second end part including closing means within said last chamberoperable to close said second nozzle means upon displacement of themovable element in the direction thereof,

the chambers having a smaller active area diaphragm means forming apartition thereof facing said first nozzle means being called evenchambers, the other chambers being called odd chambers,

at least one odd chamber having a bias input connection supplied withsaid biasing pressure, at least one even chamber having a signal inputconnection supplied with one of said signal pressures, at least onechamber other than said first chamber being open to the atmosphere, andsaid first chamber being connected with said output.

4. In a pneumatic logical circuit, a logical cell as claimed in claim 3,wherein the chamber open to the atmosphere is said last chamber.

5. In a pneumatic logical circuit a logical cell as claimed in claim 4,wherein said first chamber connected with said '10 output is an oddchamber, the other odd chambers having bias input connections and atleast two even chambers having signal input connections, the lastchamber being open to the atmosphere.

6. The combination defined in claim 3 wherein at least two even chambershave a signal input connection supplied with one of said signalpressures.

7. The combination defined in claim 6 wherein said last chamber has asignal input connection supplied with one of said signal pressures.

8. In a pneumatic logical circuit including means for supplying a fluidwith a constant feeding pressure, means for supplying a fluid at aconstant biasing pressure lower than said feeding pressure and means forsupplying fluids at signal pressures,

a logical cell, comprising:

a series of six chambers disposed contiguously, consecutive chambershaving common partition means including diaphragm means therebetween,said diaphragm means of first alternate ones of said partition meanshaving active areas of a first size and the diaphragm means of theremaining one of said partition means having active areas of a secondsize larger than said first size in a predetermined ratio,

a movable substantially rigid element mechanically connecting togethersaid active areas of the diaphragm means and having a first end part anda second end part extending respectively into the first and the last ofsaid series of chambers,

said first chamber in said series including first nozzle means forminginput means supplied with said feeding pressure and said first end partincluding closing means within said first chamber operable to close saidfirst nozzle means upon displacement of the movable element toward saidfirst nozzle means,

said last chamber including second nozzle means forming an output andsaid second end part including closing means within said last chamberarranged to close said sec-0nd nozzle means upon displacement of themovable element toward said second nozzle means,

the chambers having a smaller active area diaphragm means forming apartition thereof facing said first nozzle means being called evenchambers, the other chambers being called odd chambers,

said first chamber being connected with said output,

one even chamber having a bias input connection supplied with saidbiasing pressure,

another even chamber being open to the atmosphere,

and the odd chambers other than said first chamber having separatesignal input connections.

9. In a pneumatic logical circuit including means for supplying a fluidwith a constant feeding pressure, means for supplying a fluid at aconstant biasing pressure lower than said feeding pressure and means forsupplying fluids at signal pressures,

a logical cell, comprising:

a series of six chambers disposed contiguously, consecutive chambershaving common partition means including diaphragm means therebetween,said diaphragm means of first alternate ones of said partition meanshaving active areas of a first size and the diaphragm means of theremaining ones of said partition means having active areas of a secondsize larger than said first size in a predetermined ratio,

a movable substantially rigid element mechanically connecting togethersaid active areas of the diaphragm means and having a first end part anda second end part extending respectively into the first and the last ofsaid series of chambers,

said first chamber in said series including first nozzle means forminginput means supplied with said feeding pressure and said first end partincluding closing means within said first chamber operable to close saidfirst nozzle means upon displacement of the movable element toward saidfirst nozzle means, said last chamber including second nozzle meansforming an output and said second end part including closing meanswithin said last chamber operable to close said second nozzle means upondisplacement of the movable element toward said second nozzle means,

the chambers having a smaller active area diaphragm forming a partitionthereof facing said first nozzle means being called even chambers, andthe other chambers being called off chambers,

said first chamber being connected with said output,

said last chamber being open to the atmosphere, one odd chamber having abias input connection, one even chamber having a signal inputconnection, another even chamber being connected with said output, andanother odd chamber having a signal input connection.

10. In a pneumatic logical circuit including bias means for supplying afluid with a constant selective biasing pressure and control means forsupplying fluids at signal pressures,

a logical cell, comprising:

a series of six chambers disposed contiguously, consecutive chambershaving common partition means including diaphragm means therebetween,said diaphragm means of first alternate ones of said partition meanshaving active areas of a first size and the diaphragm means of theremaining ones of said partition means having active areas of a secondsize larger than said first size in a predetermined ratio,

a movable substantially rigid element mechanically connecting togethersaid active areas of the diaphragm means and having a first end part anda second end part extending respectively into the first and the last ofsaid series of chambers,

said first chamber in said series including first nozzle means and saidfirst end part including closing means within said first chamberoperable to close sai-d first nozzle means upon displacement of themovable element toward said first nozzle means,

said last chamber in said series including second nozzle means and saidsecond end part including closing means Within said last chamberarranged to close said second nozzle means upon displacement of themovable element toward said second nozzle means,

the chambers having a smaller active area diaphragm forming a partitionthereof facing said first nozzle means being called even chambers, theother chambers being called odd chambers, each of said chambers beingprovided with means for applying fluid thereto at a desired pressure,

at leastone chamber of one parity being supplied with said biasingpressure from said biasing means, and at least one chamber of the otherpa-rity having a signal input connection supplied with one of saidsignal pressures from said control means.

References Cited by the Examiner UNITED STATES PATENTS 2,712,321 7/1955Grogan 13786 2,774,367 12/1956 Grogan 137-86 2,864,399 12/1958 Hartz13785 X 2,935,077 5/1960 Keyser l37-82 FOREIGN PATENTS 121,289 1959Russia.

134,917 1961 Russia.

150,309 1962 Russia.

OTHER REFERENCES Berends et al.: (1), International Federation of Automatic Control, Trudy Mezhdunarodnago Kongressa, 1st, Moscow 1959, -pp.431-448.

Berends et al.: (2), Pneumatic Switching Circuits, Automatic and RemoteControl, vol. 20, No. 11, Sept. 1958, pp. 1446-1457.

Mitchell et al.: Fluid Logic Devices and Circuits, Transactions of theSociety of Instmment Technology, Feb. 26, 1963.

RICHARD B. WILKINSON, Primary Examiner.

LEO SMILOW, LOUIS I. CAPOZI, Examiners.

WAYNE F. BAUER, Assistant Examiner.

UNITED STATES PATENT OFFICE CERTIFICATE OF E CORRECTION Marcel Mamy aterror appears in the above identified It is certified th ent are herebycorrected as patent and that said Letters Pat shown below:

Column 9, line 21, "odd" should read even Signed and sealed this 22ndday of December 1970.

(SEAL) Attest:

WILLIAM E. SCHUYLER, JR.

Edward M. Fletcher, Jr. Attesting Officer Commissioner of Patents

1. IN A PNEUMATIC LOGICAL CIRCUIT INCLUDING BIAS MEANS FOR SUPPLYING AFLUID WITH A CONSTANT SELECTIVE BIASING PRESSURE AND CONTROL MEANS FORSUPPLYING FLUIDS AT SIGNAL PRESSURES, A LOGICAL CELL, COMPRISING: ASERIES OF SIX CHAMBERS DISPOSED CONTIGUOUSLY, CONSECUTIVE CHAMBERSHAVING COMMON PARTITION MEANS INCLUDING DIAPHRAGM MEANS THEREBETWEEN,SAID DIAPHRAGM MEANS OF FIRST ALTERNATE ONES OF SAID PARTITION MEANSHAVING ACTIVE AREAS OF A FIRST SIZE AND THE DIAPHRAGM MEANS OF THEREMAINING ONES OF SAID PARTITION MEANS HAVING ACTIVE AREAS OF A SECONDSIZE LARGER THAN SAID FIRST SIZE IN A PREDETERMINED RATIO, A MOVABLESUBSTANTIALLY RIGID ELEMENT MECHANICALLY CONNECTING TOGETHER SAID ACTIVEAREAS OF THE DIAPHRAGM MEANS AND HAVING A FIRST END PART AND A SECONDEND PART EXTENDING RESPECTIVELY INTO THE FIRST AND THE LAST OF SAIDSERIES OF CHAMBERS, SAID FIRST CHAMBER IN SAID SERIES INCLUDING FIRSTNOZZLE MEANS AND SAID FIRST END PART INCLUDING CLOSING MEANS OPERABLE TOCLOSE SAID FIRST NOZZLE MEANS UPON DISPLACEMENT OF THE MOVABLE ELEMENTTOWARD SAID FIRST NOZZLE MEANS, SAID LAST CHAMBER IN SAID SERIESINCLUDING SECOND NOZZLE MEANS FORMING AN OUTPUT AND SAID SECOND END PARTINCLUDING CLOSING MEANS OPERABLE TO CLOSE SAID SECOND NOZZLE MEANS UPONDISPLACEMENT OF THE MOVABLE ELEMENT TOWARD SAID SECOND NOZZLE MEANS, THECHAMBERS HAVING A SMALLER ACTIVE AREA DIAPHRAGM MEANS FORMING APARTITION THEREOF FACING SAID FIRST NOZZLE MEANS BEING CALLED "EVENCHAMBERS," THE OTHER CHAMBERS BEING CALLED "ODD CHAMBERS," AT LEAST ONEODD CHAMBER HAVING AN INPUT CONNECTION SUPPLIED WITH SAID FLUID AT SAIDBIASING PRESSURE, AT LEAST ONE ODD CHAMBER HAVING A SIGNAL INPUTCONNECTION SUPPLIED WITH ONE OF SAID FLUIDS AT SIGNAL PRESSURES, ATLEAST ONE CHAMBER OTHER THAN SAID FIRST CHAMBER BEING OPEN TO THEATMOSPHERE AND SAID FIRST CHAMBER BEING CONNECTED WITH SAID OUTPUT.